This invention relates to an electromagnetic suspension assembly for a motor vehicle.
Conventional suspension assemblies include fluid filled shock absorbers in combination with coil springs to provide the required spring and dampening forces.
Most conventional suspension assemblies are known as passive suspension assemblies because they can only react to forces input from movement of the wheel assembly.
It is known in the art to improve on such passive suspension systems by including a variable damper assembly. Conventional variable damper assemblies change the dampening force by changing flow orifice sizes or by changing the viscosity of a fluid filled damper by using a magnetorheological fluid. Variable damper assemblies improve the driveability of a motor vehicle by adjusting the dampening force depending on desired vehicle handling characteristics including traction, braking and handling. However, such suspension assemblies still only react to forces input from the wheel assembly.
It is also known in the art to include an electric motor to provide variable dampening characteristics of a suspension system. Typically, such systems utilize an electric motor rotatebly driven by vertical movement of the wheel assembly. A resistance load on the electric motor is varied to adjust and vary dampening characteristics of the damper and thereby the suspension system. However, such systems are generally utilized as an alternate means of utilizing wheel movement to generate electrical power for use in the motor vehicle.
Currently suspension systems react to force input by the wheel assembly and are unable to input forces to improve driveability of the motor vehicle. It is therefore, desirable to develop a suspension system that can both react to input forces from the wheel assembly, and input forces to the wheel assembly to provide improved motor vehicle drivability.
The invention is a suspension assembly for a motor vehicle including two generally co-axially mounted electromagnetic coils between which is generate a controlled magnetic field adjusted to provide required spring and dampening forces. The suspension assembly includes a wheel assembly movably mounted to the motor vehicle frame such that the wheel assembly moves in a substantially vertical direction in response to uneven roadway surfaces. A first inductive coil attaches to the wheel assembly about an axis, and a second inductive coil mounts co-axially with the first inductive coil and movable relative to the first inductive coil. The coils are electrically coupled to a power source controlled by a vehicle controller. The power source provides electrical power to the inductive coils to produce an electromagnetic force between the inductive coils to provide a dampening force required dampen oscillations of the wheel assembly. The variation in inductance between the coils caused by variation in the relative position of the coils to one another is used to determine a ride height of the motor vehicle.
Further, the generated magnetic force between the two coils provides a means in which force can be input into the suspension assembly instead of merely reacting to forces input from the wheel assembly. The inductive coils may be energized in a manner to increase traction by increasing the force with which the wheel assembly contacts the road surface. This provides the ability to actively control the suspension characteristics as desired to control particular motor vehicle driveability characteristics such as traction, braking and handling.
The suspension assembly of the subject invention both reacts to input forces from the wheel assembly, and inputs forces to the wheel assembly to provide improved motor vehicle drivability.